Abstract: Deese-Roediger-McDermott (DRM) paradigm was adopted in the present 2 (manner of stimuli presentation: mixed vs. blocked) ×3 (levels of conscious processing) ×3 (types of items) factorial experiment to investigate whether unconscious activation was involved in the generation of false memory.
The first and the second factors were between-subject while the third factor was within-subject. In the study phase, list of words was presented to three independent groups of normal participants. One group was instructed to identify the color of the list words as quickly and as correctly as possible, the second group was instructed to read the presented words aloud, and the last group was instructed to remember as many words as possible for a later memory test. The three types of task led to three different levels of conscious processing of the word list, i.e. unconscious, low conscious and high conscious processing. For half of the three groups of participants, the word list was presented in mixed way. While for the other half of the three groups of participants, the word list was presented in blocked way. In the recognition phase, all the three groups of participants were tested.
The results showed that there was significant interaction between item types and conscious processing levels, i.e. the false alarm rates of critical lures were higher in the condition of high conscious processing than in the other two processing conditions, while the hit rates of learned items were stable in all conditions. False memory effects appeared even in the unconscious processing condition. The results also showed a significant main effect of stimuli presentation manner on critical lures.
These results suggest that conscious processing is not necessary for the generation of false memory. Unconscious activation does exit and is enough for the generation of false memory. Furthermore, the accumulation of unconscious activation could lead to stronger false memory effect. The interruption of successive activation, however, could reduce false memory. The results are discussed under source-monitoring framework

Key words: false memory, DRM paradigm, conscious processing, unconscious activation